Forage harvesters are used to harvest whole plants or their parts, which are gathered from the field, during operation, by way of a harvesting attachment, compressed by pre-compression rollers, and are conducted to a chopping drum, whose chopper blades cut the plants, in conjunction with a counterblade. Subsequently, the cut plants or parts are optionally conducted to a conditioning device and conveyed to a discharge spout, by way of a post-acceleration device; the cut material is then loaded onto a transporting vehicle. The harvested plants, generally, are used as animal fodder or for the production of biogas. The conditioning device usually comprises two or more rollers, driven in opposite directions, which are pre-tensioned, relative to one another, by a spring force and between which, the chopped material is conducted through. It is used during the corn harvest, to beat the grains contained in the chopped material and to improve the digestibility of the fodder.
The rollers of the conditioning device are usually provided with teeth or edges extending in the axial direction, so that a noncircular, profiled cross section of the rollers is obtained (see DE 83 02 421 U1).
Furthermore, embodiments of rollers, profiled in the axial direction, have been proposed, which, for example, have flanks that are composed of straight-line inclined, rising (DE 41 22 338 A1) or stepped (DE 197 03 486 A1) or curved (DE 101 51 246 A1), or curved and straight sections (DE 10 2005 053 092 A1). These rollers also have teeth in the circumferential directions and the areas of one roller that have a larger diameter are located opposite the areas of the other roller that have a smaller diameter, so that the (zigzag or meandering) processing gap between the rollers has at least an approximately constant width over its length. One advantage of these rollers, profiled in the axial direction, is that the processing gap is longer than with rollers that are not profiled in the axial direction. In addition, the radii and thus the circumferential speeds of the points of the rollers, which mostly define the processing gap, differ, which improves the processing of the harvested material.
On the other hand, in a manner different from rollers that are not profiled in the axial direction, crop residues accumulate in the indentations of the rollers profiled in the axial direction, which can be removed only insufficiently by scrapers adapted to the profile of the rollers. Such crop residues rub on the other rollers and on housing elements of the conditioning devices, which increases the wear and tear of the rollers and they can also lead to clogging of the conditioning device.